1. Field of the Invention
This invention generally relates to a shifting control apparatus. More specifically, the present invention relates to a bicycle shifting control apparatus for moving an electrically controllable front derailleur between multiple sprockets that are aligned so that the number of teeth increases outward in the axial direction.
2. Background Information
Bicycling is becoming an increasingly more popular form of recreation as well as a means of transportation. Moreover, bicycling has become a very popular competitive sport for both amateurs and professionals. Whether the bicycle is used for recreation, transportation or competition, the bicycle industry is constantly improving the various components of the bicycle. Recently, bicycle gear shifting control systems have been extensively redesigned so as to be electrically operated.
Externally mounted gearshift devices which operate a front derailleur and rear derailleur are known as bicycle gearshift devices. In externally mounted gearshift devices of this type, a gearshift operation is performed as a result of the chain being moved by the front derailleur to one of a plurality of front sprockets that are lined up in the axial direction and mounted on the crank axle, or being moved by the rear derailleur to one of a plurality of rear sprockets that are lined up in the axial direction and mounted on the rear wheel hub shaft. In such externally mounted gearshift devices, gearshift operating parts that can cause an electrically controllable derailleur (which can move the chain by an actuator such a motor or the like) to perform a gearshift operation have been known in the past (for example, see Japanese Laid-Open Patent Application No. 2005-238873).
With conventional techniques for controlling gear shifting by using an electrically controllable derailleur, the gears are shifted up or down at the press of an operating button in a gearshift operating part, for example. When the gears are downshifted from a large-diameter sprocket to a small-diameter sprocket with the front derailleur, sometimes a phenomenon known as chain skip occurs, in which the chain moves further inward past the small-diameter sprocket and comes off. When the chain skips, sometimes the rider must stop the bicycle, lay the bicycle down, and manually return the chain to the sprocket. Therefore, sometimes the bicycle can no longer be ridden when the chain skips, which may cause a crucial delay if the chain skips during a race.
In view of the above, it will be apparent to those skilled in the art from this disclosure that there exists a need for an improved bicycle shifting control apparatus. This invention addresses this need in the art as well as other needs, which will become apparent to those skilled in the art from this disclosure.